Motional correlation in reduced band width television



Sept. 15, 1953 R. E. GRAHAM 2,652,449

MOTIONAL CORRELATION IN REDUCED BAND WIDTH TELEVISION Filed Dec. so, 1949 5 Sheets-Sheet '1 f g y :1

| L I l MOSAIC ,4 MosA/c a MOSAIC c X x x 1' n!) f (m!) f (XWQJH' (SUBJECT DISPLACEMENT -A, -k 1 a 1 U/VDELA r50 cams/=- F/EL 0s DELAYED COARSE FIELD STORAGE MOSA/CS GOA/P55 VIDEO SIGNAL A /0 2 OUTPUT fii" INPUT 62 RE'CT M63 66 SCAN MIX CIRCULAR/54 DELAY sc 1v NETWORK 30 a /v G c 3 3, 2, H

6/ I I 7Q 6 'FQ MIX ANALYZER was. e CIRCUITS MO r/0/v V 1/69 SIGNAL OUTPUT CORRECTIVE r0 BEAPPL/ED r0 DEFLECT/ON RECOVERY SCAN OF Fla 3 FEEDBACK FINE STRUC TURE Flap).

' 42 v JUM 54 LPF,LTER/ p+r 5/ AMP! P 5 cos Zwt 43 56 4/ 46 4a 58 :t LPFILTER p r I r I 4.2mm? 47 U E SW 2102 INVENTOP R. E. GRAHAM Arron/v5? Sept. 15, 1953 R. E. GRAHAM 2,652,449

MOTIONAL CORRELATION IN REDUCED BAND WI DTH TELEVISION Filed Dec. 250, 1949 5 Sheets-Sheet 3 FIG. 6

MULT/PL/ER P P Pr /26 /23 12a /24 r 58 25; Z Pff an; /Pr1 REC /22 12: [29 z SOUAR/NG Z CIRCUIT Pzr 5 my TO GAIN CONTROL uvnurs FIG. 7.

132 /s/ AMP 13s L eg MULTIPL/E'R 134 c/Rcu/r s a MODULAT/NG SIGNAL 3 6 e a) K, 133 /37 C;

(GA/N CONTROL INPUT) FIG. 8

I32 I36 6 A 0 lNl/ENTOR R E. GRAHAM ATTOR NEY Sept. 15, 1953 MOTIONAL CORRELATION IN REDUCED BAND WIDTH TELEVISION Filed Dec. 50,

VIDEO S/GNAL R. E. GRAHAM 1949 5 Sheets-Sheet 4 FIG. 9

TRANSMISSION MED/UM COARSE m $9222 I 1 L P SIGNAL I C/RCU/T or F/L FIG. 2 2/2 SUM I I 69 AMP.

I MOT/0N I I SIGNAL I 2/4 OUTPUT I 1 1050 I H. R sromar I STORAGE S/GNAL FILTER TUBE I TUBE l3 zos \207 209 I I \2/0 I WARPED FINE F/NE VIDEO SIGNAL SIGNAL lNl/ENTOR R. E. GRAHAM BY I a ATTORNEY R. E. GRAHAM MQTIONAL CORRELATION IN REDUQED BAND WIDTH TELEVISION Filed Dec. 50, 1949 5 Sheets-Sheet 5 /NVENTOR R. E. GRAHAM 5V ATTORNEY Patented Sept. 15, 1953 :MO'IIONALJGORRELATIONJIN REDUCED BAN EWIDTH TELEVISION Robert E, Graha rn Morristown, N. J .,,assignor to "Bell Telephone Laboratories, Incorporated, New York, 'N. -Y ;a corporation of New York App icati n. December- .49,S.e e N -..13.6,1;0

(o1. ts-58) Claims. 1

This in entio relatestath enshfiaatmnsmis o 7 recept on an r r u of el tri ion -signals .na ula l television enals a d e=-li e .I.. o e ici nehappl cat o 1 t resen inventor, Serial hie. 136,105, filed December 3,9, ;949 r.l' I.l. $-:i ni c sed a s s f r t du on-s he ra smis ionban wi te i i n mage. s nals in l rhieh th v du t o is ach ved by discarding amajor portion of the fine detail video in rm onf 'he o rat n. of h s sem is .suehthM-when th i ppr ab tm ion i th -televis s n th m cur a h riec ee b tween the coa s andth fine truc u e inc rth coars vide conten .Q th .ishmueh no to dat mo r quently o e e deta l-vi eo. iormeti al 's-t erefore th pr nci alsbi ctoft r nt t. ention-t l .n nat the imper e rears.- e ail-m y oc u w e ath vcoar a th n vids struc ur i t a t d tele isi n andwi th-reducti n c eme o t e e ra tyr asth di c osed i theahov n nti ia oncedin ap ication in a cord nc with th re t nan i u hnr no ;o ts11bma ob-ie wfi m u e c cui are. m loye t iyie dhs enal ap roximati -th ec com onent of mot o i th p ctori subi ta. -t e creased to warnt vfis ru uretto n i ntoeei t it th oars structu e- :T accom l s hismonete emn ar embqcii entp that v nt ne nn q techni ue for st in th rq s sfieldl s na simu taneou on thewmose cs of tw s ora t bes Atten B, andzf ristor n ns av d-ver i n 0f t e coa s fi tsien con -i h rdvr t ae ub Q n rec verine th im si na tram t e tm saie a lt re a e an edsy hron usly in, the noral scann n p tt aha. i dd t on a hi r quen a-... req en y g compar d wit th t ni creou n y 21 h c a sezs en w cir ula scan oi -circle I size comparable with anfleleme tal areaof the coarsesystem is superposedton the r a :sc n ,-pa ter of os ics ,-.B nd The signals recovered; from these three-mosaics, from; which man be obtained in,accorda nce with the invent n th moti na vin o. rma in es ed the un er com u e o e t whi e1 si a appr x mat n th v cto components ofthe motion which has; actually ocourred in the elevis l en I i th s ou u si na whi h au e .t were hetde ay d i s ructu .in accordance With the invention.

-;1 i vention zwil uhetmur i l; u erstead om th -:f.ol .owing de ai e ;descrip io ;-to a e 2 c am i t at embodiments th e ta en connection with the appended drawings forming a part thereof, in which: 7

Fig. 1 illustrates the geometrical relationships of the three storage mosaics of the invention;

Fig. 2 is an over-all block diagram of one specific embodiment of the motion computer;

"Fig. 3isa'b1ock diagram of one exemplaryarrangement for the measurement of the differential coefiicients;

"Fig. 4 is an over-a-ll block diagramofthe same specific embodiment of the-inventionehown in Fig. 2, containing certain details not found in Fig. 2, but omitting others therein shown;

-Fig.' 5'is ablock-diagramof the alternate computer paths in one embodiment of the motion computer which is of value in the so-called boundary case;

Fig. 6 is a bloch diagram of circuits which can be employed in the practiceofthe'invention-to yield signals servingas inputs to the several gain control circuits;

"Fig. 7 shows one illustrative embodiment of a reciprocal gain control circuit which can be utilized the invention;

'Fig. 8 illustrates another exemplary embodiment of a reciprocal gain control circuit; and

"Fig. '9'is an over-al1"blocl diagran' of a simple illustrative embodiment of a reduced band width television system in which the present invention is employed; and

Fig. 10 illustrates schematically an arrangement 'for performing the computerl operations calledjor in the system shown in-Fig 2. I v

Th .s qm tr c ignifi anc o t s a n ran eme o th invention i 7 b a paren rqm'referennc t i 1 .frh c ar i ml, which ma b forme accorda c wit 'th ech iq e and m oying the a para u li fi in .m a de itified o end ne iqa n. i stereo .Qn m sei se and B iel h s a d 20, resneqtire h and h n dela ed b on .iramet me is st red a aemia a thir m saicpi ext n vf thes i s 'c r narts .o vc uitab eostorae tu es T embite .d iri uti ns on th s imqsaic lqa b co enie t descri edasthevtw rdime si n fii i iqns new sta th emanate he endzaq mn m resn ct re v'l l th ubi-es -rqi nla mfintrtheth q me th eqe ayt.in tand@re lthenis v ;v. on v of the coordinates x, y. The type of subject change which is being considered here is, of course, primarily that due to lateral motion of regions of the picture, and does not include sudden changes of scene. The problem is to determine the components h, k for each elemental area of the picture from a comparison of the Original and the delayed coarse fields. By the nature of the problem, this motional information must be immediately available at any given point in the raster while that point is being scanned, and, in accordance with the invention, such information is both made immediately available and utilized to eliminate any imperfect register which may occur as the result of the motion.

To measure the amount by which a picture convolution centered at a point x, y has been displaced, it is obviously-necessary to measure at least the second order partial derivatives of the voltage distribution function at that point,

6 1' 1 and A measurement of these derivatives at any point necessarily requires certain information concerning the immediate area surrounding the point, and, in accordance with an exemplary embodiment of the invention, the method chosen to obtain this information involves the superposition of a high frequency circular scan upon the normal scanning pattern used to recover the coarse time signals from storage mosaics B and C (elements 20 and 30). The frequency of revolution of this scan is made high compared with the top frequencies in the coarse signal, so that, for an R. M. A. standard 525-line television system, for example, a feasible value of the circular scan frequency can, as an illustration, be 10 megacycles per second, and a similar illustrative value of the radius can be one-fiftieth of the picture height. In addition to this high frequency circular scan, which is superposed only for mosaics B and C, all three mosaics are scanned synchronously in the normal scanning pattern, such as, e. g., the 525-line rectilinear interlaced pattern which is customarily employed in standard American commercial television practice.

An over-all block diagram of an illustrative embodiment of the motion computer is shown plete video signal with electrical filters to separate the coarse and fine components or as the result of separation by coarse and fine image dissector tubes. The storage scan is carried out in the normal rectilinear pattern for all three mosaics, this normal scan being generated by a rectilinear scan generator 63. For the recovery scan, mosaic A (element l) requires the same rectilinear pattern, while mosaics B and C (elements 20 and 30) require the rectilinear pattern plus a high frequency circular scan supplied by a circular scan generator 64. The combined rectilinear and circular scanning pattern for these two mosaics is produced by electronic mixing of 4 the outputs of the two scan generators in mixers E6 and 61, in accordance with well-known electronic techniques. A special feature of the specific embodiment of the invention shown in Fig. 2, which, it is to be understood, is not a necessary feature for the properfunctioning of the invention, but which possesses certain advantages, is that the motion signals 69 obtained from the computer are fed back to the deflection system of mosaic C to cancel the effects of the original subject displacement. The principal advantage of this feedback arrangement is that the various computations need not be performed accurately. Thus, mixer 61, whose output determines the recovery scan from mosaic C, has as a third input a feedback deflection signal 69. The time signals ll, 2|, and 3| recovered from the three mosaics I0, 20 and 30, respectively, are operated on by a group. of analyzer circuits 68 to yield the desired motion signal output 69 to be applied to the recovery scan of the fine structure field and, in the feedback version of the invention, to theC mosaic (30) deflection system as well (via mixer 61). The operation of this analyzer 68 will be discussed in greater detail with reference to Figs. 3 and 4.

In Fig. 9, there is illustrated the relationship of the present invention to that of the aboveidentified copending application. For purposes of illustration, in Fig. 9, the circuit of Fig. 2 is shown in block form as constituting the present invention. Also for purposes of illustration, the simplest embodiment and most schematic representation of the invention of the copending application has been shown in Fig. 9. It is, of course, obvious that any of the several arrangements of the present invention can operate perfectly well in conjunction with any of the several embodiments of the invention of the copending application. As indicated in Fig. 9, a conventionally generated video signal 20! is split into two transmission paths 203 and 204 containing complementary low-pass and high-pass filters 205 and 206. In a specimen arrangement, the transmission band of the low-pass filter 205 can extend from zero frequency to approximately 10 per cent of the normal top video frequency; while that of the high-pass filter may start at about 10 per cent of the normal maximum frequency. The signal from the low-pass filter is transmitted directly in accordance with standard practice, but the high-pass signal is first recorded on the mosaic of a storage tube 201. The pick-up beam of the storage tube is scanned in the same geometric pattern or raster as the recording scan but at a much lower repetition rate, which, to choose an illustrative value, can be one-tenth of the recording rate. Thus, the outgoing collector signal 209 is a slowly repeated version of the original by-pass video signal from the highpass filter. At the receiver, the modified (i. e., having a reduced repetition rate) fine structure signal 209 is stored in a storage tube Zlfl similar to the one used at the transmitting point, but the recording scan is now carried out at the low repetition rate and the pick-up at the original high repetition rate, thereby producing an output time signal identical with the original fine structure signal when there is no motion in the televised scene. The coarse video signal, however, is applied to a circuit 2| I, which represents the present invention as illustrated in Fig. 2. This circuit 2 yields two outputs, viz., a motion signal 69 and a simple coarse video signal 2l2 which corresponds to the output of the lowpassrafilter 5205. Theimotionxsignal -69 a iseapplied to thapick-upscan of: the storage: tube '2 H1, and its efiectis to warp thefinevid-eo .-signal .so' as" to bring'it-into register -with': .the'coarse1signal, as discussed elsewhere herein. This warped fine video vsignal M3 is then added Kin-summation amplifier .ZM) .to the ooarse2-video:signa1i212:to form a complete video signal 215 'once more, which signalarcan: beLu'sed to reproduce the television image in the usual way.

It i is evident that the signalcderivedfrom Imosaic A elementilll) can betexpressedusimplyaas 'Mray) =f(n:,: r 1) where xxandsy 'are functions-of time accordingto the rectilinear scanning pattern. The -.-expression for the B andC:signalsearewcomplicated-.by the superposedcircular scan and: that: for the .C signal mis further complicated by the time delay (whichlintroduces the increments due to subject motion), but it is readily demonstrable through the use of a *Taylors expansion (neglecting higherorder terms) and otherrstraightforward mathematics, that the B signal can convenientlybe expressed as 1'('R sin awe-1 2m sin-wt) 2q(hk+kR cos wt+hR sin-wt-i-R sin wt cos Where o of and it is readily seen that the bracketedgroupwof termsin this expression contains the desired information' about the differential :coeflicients-p, q,

andr. This information isautilized in an exemplary embodiment of the invention .in' the manner illustrated in Fig. 3.

The term in (21+r) isi filteredout as -:a video frequency signa15l by means of a ;lowepass.filter 42. Th terms'in (p- 7) and q. areseparated. out by" applying. the (fb'fa). signal M-Itora pair'of phase selective demodulators 46 :andALsu'chcas are well knownin the'ele'ctronic art, demodulator dfiibeings'supplied'with a carrier E"cos"2 wt and -demodulator 41 'Witha carrierE sinzwt, in accordance with well-knownwelectronic techniques. LThe outputs, 48 and'149, respectively, of these twoclemodulators then, pass. through low-pass. afilters 4'3 and dflgrespectively;thereby vyieldimrvideo frequency signalsfiiZ land 53,. respectively proportionalto (p-r) anclzq. By combining the )-Pr) signal l and-the (I signal 52 man ordinary summation amplifier 54, a signal 5l,vrepresentative of-the difierential coefilcientgptds obtained, and-a similar combination-of: signals 5 I and: 52

6 in amconventional difienence amplifier-afivyieldsra signal .58 which is representative of the xfCOemcient r.

The manner in which .nthese :coefliei-ents tare utilized in thezoperationofithe inventionsisashown in.'Fig. 4, 'rwhichiis likerl iigafi, an oversall-rgblock diagram aof tthfi illustrative feedback version of the motion .computer,:but: whichincludesrcertain details snot tot he found .2 in! Fig. :2, while remitting others which :are -sufiicient ly;rset, forthiin that-figure. Before:referringzsspecifically to a-Fig. 1, however, it wil1 be-of valuetoaexamineanimportant mathematical relationship. @If ;the TB ssignal 3ft (Equation-.2) .is-lsubtnactedrirom the C-lsignal fa (Equation 3), there: results 1711+ qk)R cos (fit-j Qq'h +7k) R;SiI1-ml,

'It' is -evidentthat 'the bracketedgroup of terms in Equation-'5 constitutes avideo' frequency-signal, while "the "second 'and third "groups consist of video frequency modulations "of the high "frequencycarrier (of angular velocity-(b). Asshown in Fig. "4, *t-he entire "signal 1| represented by Equation- 5 is applied to a pair of phase=selective demddulators 12 and 13, demodulator 12 *being supplied 'with a local carrier Ecos'ot-and"demodulator "13 vvithacarrier al sin-wt. In this manner, two videofrequency 'signals-l'band IS -are separated out, M being proportional to (pk-Mk) and 16 to (oh +440. "These quantities'caneonvenienh lybe represented" as *M and N, such that .(6) and and.

"Since the differential coeilicients p, "q, and '1' havebeen determined by the operation of a'circuit' such as that "illustrated in'-Eig.'-3, a ll 'that remains to obtain motion signals-*proportionat to hand-7c is to performthe addition, multiplication, and division indicated-in Equations 8' and" 9, an'd these-operations can be -carrie'd' out by circuits that are wellk-nown in the electronic art, utilized, for. example,:zin the: manner showna in Fig.4.

The over-all operation .of an...illustrative--embo'dimentof the. feedback: rtype motion computer is also shown in 4. :Theeefiects 10f the-subject motion 'sare rrepresented .as the; input components, --ih.:and- (11 and r18,-=:respective1y) The: corrective deflections-hue to; theixmotionzsignal' feedback arerrepresentedrby. the. components 6w .andr-fiy (19san'd58l,wrespectively) 'Thesez two sets-:of :components x-oppose each. other, 5. as 4 indi cated. symbolically :by ,thexdifierential mixers -82 and 83,.:inwhich; thetamand; the .y components, respectively, are combined. :Thus,:. the :net relative-vdisplacementssat:the=, C mosaic'tare tn-Hm) and (Io-My) The remaining T-SOUYQGFOf input :information. is the coarse field: imageitself, flaw) This-coarse held image 15 undergoes a series of scanning and a storage :processes in a -;group of circuits I'E, whose operation is shown in; greater detail :in-Figs; 1 2 and Land has. been discussed in: connection: therewith. .Inl thatthe. exemplary embodiment of the invention shown in Fig. 4 isafeedback version of the motion computer, it is obvious that the quantities h and k which have hereinabove been discussed are replaced by quantities (h-I-tm) and (lc+6y). The signal 14, representative of the quantity M, is fed to two multiplier circuits 84 and 86, which are supplied, respectively, by signals 58 and 53, which are representative, respectively, of the quantities rand q. These signals, as well as a signal 51, representative of the quantity p, are derived from agroup'of circuits 35 which were above described in greater detail in connection with Fig. 3. The signal 16,representative of N, is similarly applied to multipliers 81 and 88, which are supplied by signals 53 and 51, respectively, representative of quantities q and p, respectively. The output signal 9I of multiplier 84 (representative of TM) is then added to the output signal 93 of multiplier 81 (representative of -qN) to yield a signal 98 which is representative of the numerator (rM-qN) of Equation 8 above for the x component (it) of subject motion. In like manner, the output signal 92 of multiplier 86 (representative of -qM) is added to the output signal 94 of multiplier 88 (representative of pm to yield a signal 89 which is representative of the numerator (pN-qM) of Equation 9 above for the 1/ component (k) of subject motion. These operations thus completely divorce the :v and 3/ components of the motion signal. The signals 98 and 99 are then transmitted through amplifiers 96 and 91, respectively, each of which has its gain controlled roughly as (p1fq by a group of circuits 50, shown in greater detail in Figs '7 and 8. The output signal IIlI of amplifier 98 now represents the a: component (h) of the motion signal (see Equation 8) and it is fed back, in this particular version of the invention, to the a: deflection control I03 of the C mosaic 30 to yield a spatial subject motion component 19 (5x) which is compared with the actual subject motion component (-it) in the differential mixer 82, as discussed above. Similarly, output signal I02 of amplifier 91 represents the 3 component of the motion signal (see Equation 9) and it is fed back to the y deflection control I04 of the 0 mosaic to yield the approximate y component of motion 8|, which is compared with (-k) in differential mixer83. Provided that the gains of both the x and y loops are kept high, the resulting deflections I9 (60:) and BI (6y) will be closely equal to 'I'l (-h) and 18 (k), respectively, and thus the deflection voltages may be taken as a measure of the subject motion.

The advantage of the feedback arrangement in this exemplary embodiment of the invention is, as explained above, that the various computations need not be performed accurately, the prime requirement being that the a: and y loop gains be kept moderately high. The function of the automatic gain control is to maintain a negative polarity of transmission around the feedback loops regardless of the signs of p, q, and r,

and to keep the loop gains from varying toogreatly. If the multiplying and combining operations leading to the voltages representative of (rM-qN) and (pNqM) are performed inaccurately, there may occur cross-coupling between the a: and y loops, but it can be shown that cross-couplings of the order of 30 to 50 per cent willbe tolerable It can readily be shown algebraically that in the situation Where pr=q no-solution can be found for h and k by the means described above. Even for values of p, r and q which nearly satisfy this relationship (which will be referred to as the boundary case), the gain required of the controlled amplifiers 96 and 9'! will be excessive and the loop'gains will drop off. Thus, in accordance with the invention, an additional exemplary embodiment is provided which includes an illustrative feasible arrangement for circumventing this difliculty. It can be shown that it is not necessary in the boundary case to know the individual components It and k, since any deflection which undoes the effect of the original subject motion will suifice. The simplest choice, therefore, is to introduce the corrective deflection along the normal to the contour lines, thereby effectively treating the component of subject motion normal to the contour lines and ignoring th component parallel thereto, and this is done in the specific embodiment of the invention now to be discussed It is demonstrable that the required a: and y correcting deflections in this exemplary arrangement are given by where the chosen sign of the is the same as.

the sign .of q. It is also readily demonstrable that for the so-called boundary case (p1'=q or q=i /pr the expressions for M and N are M=phvfrk (12) and N=: /E'h+rk (13) In Fig. 5 there is illustrated one exemplary embodiment of the invention which is feasible for vboundary case operation. Signals 14 and 16,

representative of M and N, respectively (generated as described in connection with Fig. 4) are tapped off and fed to amplifiers III and H2, respectively. These amplifiers are gain controlled in such a way as to have zero transmission except when the absolute value of the quantity (pq is very small, i. e., when the boundary case is approximately realized. It is worthy of note that it is not necessary to disable the normal path under this condition, since its outputs go to zero. The outputs II3 and H4, respectively, of amplifiers III and II2, respectively, are connected to amplifiers H8 and III, respectively, which are gain controlled approximately as (p+r) thereby yielding signals H8 and H8, which are respectively the :c and y deflection signals. The outputs of amplifiers H6 and II! are connected in parallel with the deflection outputs HH and I02 of the normal path, so that the composite system thus formed will operate satisfactorily for all combinations of p, q and r.

In the practice of the specific embodiment of.

the invention illustrated in Fig. 4 and discussed in connection therewith, an automatic gain control proportional to the reciprocal of the quantity- Ipn-q) is required, and in the exemplary :embodiment of Fig. 5,, two gain controls, one proportional to the reciprocal of the absolute value of the quantity (pr-q and the other proportional to the reciprocal of the quantity v(10-14), are employed. An illustrative example of a system which can,'in accordance with the invention, be used to furnish these gain controls is shown in Fig. 7, and an alternative arrangement is drawn in Fig. 8, while Fig. 6 illustrates a specimen system of providing gain control input signals.

Referring now to Fig. 6, signals 5! and 58, representative, respectively, of the quantities p and 1- and generated according to the techniques discussed in connection with Fig. 3, are fed to a multiplier circuit I2I to yield a signal I26, which is representative of the quantity pr. In addition, a signal 53, representative of the quantity q and'also generated in accordance with the circuits of Fig. 3, is squared in a squaring circuit I22, several forms of which are Well known in the electronic art, to yield a Signal I21, representative of the quantity Q2. The signals I26 and I2! are then combined differentially in a common difference amplifier I23, providing an output signal I 28,, representative of the quantity ('q -pr). Part of this output signal I 28 passes through a full-wave rectifier I24 so as to yield a resultant signal I29, representative of the absolute value of the quantity (prq while part of output signal I 28 is fed to the input of one of the gain control circuits. The other gain control inputs are provided by signal I29 and a signal 5|, which isrepresentative of the quantity (13-1-1) and is generated in accordance with the arrangement described in connection with Fig. 3. These gain control inputs, in accordance with one embodiment of the invention are each fed to a divider circuit of the type shown in Fig. 7.

The amplifier I3I of Fig. 7 represents symbolically any of the gain-controlled amplifiers which are used in the practice of the invention, viz., amplifiers 96 and 91 of Fig. 4 and amplifiers II I, H2, H6 and III of Fig. 5. It is evident then that the desired operation of the circuit of Fig. '7

is to divide a signal I32- (herein designated War), which represents symbolically any of the respective input signals (such as 98 and 99, for example, in Fig. 4) to the several gain-controlled amplifiers, by another signal I33 (herein desig-- nated e2), which represents symbolically any or the respective gain control input signals to the several gain-controlled amplifiers. This input signal I 33 is, of course, supplied by any one of the output signals .5], I28 or I29 of Fig. 6, according to the particular function of reciprocal gain control being employed.

If it is assumed that the amplifier characteristic p of amplifier I3! has substantially zero phase and constant amplitude over the range of frequencies in interest, then, within that frequency band, ,u is simply a real number. It can further be assumed that the multiplier circuit I34 is characterized by a gain relative to the signal I36 (the output of amplifier I3l herein designated 63) which is given by where k is a constant of the multiplier circuit and VB is. a properly chosen bias I31. A, ling-type modulator, such as is well known in the electronic art, can, for example, be made to work in and constant overthe frequency band.

10 approximately such fashion. It is then readily demonstrable that A ia 0H6, p.

In accordance with the invention, the bias V0 can be made equal to "so that ex is simply which is the desired relation for the divider circuit, since e2 is, in the several circuits employed, supplied, respectively, by signal 5| (representative "of the quantity (p-l-rl), signal I28 (representative of the quantity (-q -m) and signal I29 (representative of the absolute value of the quantity (pr-(1 It is to be noted that, in the example of practice just described, the loop gain is so that when ez=0 there is unity positive feedback and the amplifier I3I imparts infinite gain -;to a signal I32 (e1). And, when ,dcez becomes xdescribed arrangement can safely be used for any values of ikez.

An alternative arrangement which can be used to provide the reciprocal gain controls in accordance with invention is shown in Fig. 8. This circuit is similar to that of Fig. 7, except that the bias signal I13?! (V0). of that figure is eliminated and a shunt transmission network MI, having a transmission characteristic is added to the multiplier circuit 134 (now designated 13 1). It can readily be shown that this produces the desired over-all relation, as before. This circuit is somewhat more simple to construct in practice than the one of Fig. 7, since it is not a requirement of this alternative arrangement to have the transmission characteristic i phaseless It is sufficient merely to approximate the reciprocal of a in the added transmission network I M around the multiplier I34.

In summary, it can be seen that the analyzer circuits 68 shown in Fig. 2 for providing the motion signal outputs 69 can be represented as shown in Fig. 10 by an arrangement of electronic calculating elements, all of which can be of a kind known hitherto in the electronic art. For example, suitable calculatin elements are described in volume 21 of the Radiation Laboratories Series, entitled Electronic Instruments, published by McGraw-I-Iill Book Company, Incorporated, New York (1948 Therein, addition and subtraction elements are described on pages 41 and 42.; multiplication, division and squaring elements are described on pages 48 through 60; and phase detecting-elements are described on pages 383 through 386. Suitable dividing ele- 1 l ments have also been described more particularly with reference to Figs. '7 and 8 in this specification.

With particular reference now to Fig. 10, the three signals I I, 2|, and 3| (fa, ft, and f) derived from mosaics A, B, and C, respectively are supplied to the differential amplifiers 30! and 302 and there is obtainedtherefrom the difierences (fbfa) and (fc-fb), respectively. As has been described above with reference to Fig. 3, by means of the phase detectors 46 and 41, the low-pass filters 42, 43 and 44, and the summation and differential amplifiers 54 and 56, respectively, there can be derived from the difference (,fb--fa) measures of the differential quantities p, q and T, which have been defined above. From these quantities, by means of a multiplying circuit 303, the squarer 3M, and the differential amplifier 305, there can be obtained a measure of the quantity (pr-q which appears as the denominator in the fractional expressions (8) and (9) developed above for the desired signals h and k, respectively. An arrangement of this kind has been described in more detail above with reference to Fig. 6. Similarly, as has been described above, with reference to Fig. 4, from the difference (J,fb) by means of the phase detectors 12 and I3 and suitable filtering, there are obtained measures of the quantities M and N which have been defined above. From these, in turn, by means of the multiplying circuits 84, 86, 81 and 88, and the measures of the quantities p, q and 1, already obtained there are derived the quantities (rMqN) and (QN-qM) which appear above as the numerators in expressions (8) and (9), respectively. Then, by means of the amplifying and dividing circuits 96 and 91, which more particularly can, for example, be of either of the forms shown schematically in Figs. 7 and 8, there can be derived the outputs 69, the h and it signals which represent respectively, the desired a: and y deflection signals for use as described with reference to Fig. 2.

It should be noted that the several specific embodiments of the motion computer hereinabove described interpose only a fixed delay between the signals to mosaics B and C. Application of the invention to the basic band width reduction system of my copending application requires, on the other hand, a delay which varies cyclically, because of the nature of the storage operations upon the fine detail video signal. The rest of the computer circuits would be unaffected by the insertion of the cyclical delay. Such a delay can, in accordance with the invention, be provided, for example, by carrying the coarse signal through the identical sequence of storage operations undergone by the fine signal.

It is to be understood that the above-described arrangements are illustrative of the application of the princi les of the invention. Numerous other arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. In a television system in which separate signals are formed representing fine and coarse detail of a pictorial subject, means for discarding periodically a portion of the fine detail signals, means for deriving from said coarse detail signals a resultant signal having information relative to the motion of said pictorial subject, and means for producing from said fine detail signals which have not been discarded, from said coarse signals,

12 and from said resultant signal a television image signal representative of said pictorial subject.

2. In a television system in which separate signals are formed representing fine and coarsev detail of a pictorial subject, means for discarding periodically a portion of the fine detail signals,

means for deriving from said coarse detail signals a resultant signal having information relative to the motion of said pictorial subject, means for operating on said fine detail signals which have not been discarded with said resultant signal to form an altered fine detail signal, and means for producing from said altered fine detail signal and from said coarse signals a television image signal representative of said pictorial subject.

3. In a television system in Which separate signals are formed representing fine and. coarse detail of a pictorial subject, means for discarding periodically a portion of the fine detail signals, means for deriving from said coarse detail signals a resultant signal having information relative to the motion of said pictorial subject, said means including a plurality of storage tube devices, and means for producing from said fine detail signals which have not been discarded, from said coarse signals, and from said resultant signal a television imag signal representative of said pictorial subject.

4. In a television system in which separate signals are formed representing fine and coarse detail of a pictorial subject, means for discarding periodically a portion of the fine detail signals, means for deriving from said coarse detail signals a resultant signal having information relative to the motion of said pictorial subject, said means including a plurality of storage tube devices, means for recording said coarse signals on all but one of said storage tube devices, and means for recording a version of said coarse signals delayed by a predetermined period of time on the other of said storage tube devices, and means for producing from said fine detail signals which have not be discarded, from said coarse signals, and from said resultant signal a television image signal representative of said pictorial subject.

5. In a television systemin which separate signals are formed representing fine and coarse detail of a pictorial subject, means for discarding periodically a portion of the fine detail signals, means for deriving from said coarse detail signals a resultant signal having information relative to the motion of said pictorial subject, said means including a plurality of storage tube devices, means to operate the pick-up scans of said storage tube devices synchronously in a normal rectilinear scanning pattern, and means additionally to operate the pick-up scan of two of said storage tube devices in a circular pattern, and means for producing from said fine detail signals which have not been discarded, from said coarse signals, and from said resultant signal a television image signal representative of said pictorial subject.

6. In a television system in which separate signals are formed representing fine and coarse detail of a pictorial subject, means for discarding periodically a portion of the fine detail signals, means for deriving from said coarse detail signals a resultant signal having information relative to the motion of said pictorial subject, said means including a plurality of storage tube devices to which said coarse detail signals are applied, means for recovering from said storage tube devices signals containing said motional information, and analyzer circuit means for operating on said recovered signals to yield said resultant sig- I3 rial, and means for producing from said fine det il signals which have not been discarded, from said roarse signals, and from said resultant signal a television image signal representative of said pictorial subject.

7. A system for estimating the motion in a televised pictorial subject, said system comprising a plurality of storage tube devices to which video signals representative of said pictorial subject are applied, means for recovering from said storage tube devices signals containing motional information concerning said pictorial subject, analyzer circuit means for operating on recovered signals to yield resultant signals having information relative to the motion of said pictorial subject, said analyzer circuit means including means for subtracting the signal recovered from one of said storage tube devices from the signal recovered from another of said storage tube devices, and means for operating on the difference signal produced by said. subtraction with a pair of quadrature phase detectors so as to yield signals containing information relative to thevectorial components of motion of said pictorial subject, and means for feeding back said resultant signals to one of said storage tube devices.

8. A system for estimating the motion in a televised pictorial subject, said system comprising a plurality of storage tube devices to which video signals representative of said pictorial subject are applied, means for recovering from said storage tube devices signals containing motional information concernin said pictorial subject, analyzer circuit means for operating on recovered signals to yield resultant signals having information relative to the motion of said pictorial subject, said analyzer circuit means including means for subtracting the signal recovered from one of said storage tube devices from the signal recovered from another of said storage tube devices, and means for operating on the diiference signal produced by said subtraction with a pairof quadrature phase detectors so as to yield signals containing information relative to the vectorial comapproximating the vector components o motion of said pictorial subject.

9. A system for estimating the motion in a televised pictorial subject, said system comprising a plurality of storage tube devices to which video signals representative of said pictorial subject are applied, means for recovering from said storage tube devices signals containing motional information concerning said pictorial subject,

analyzer circuit means for operating on said recovered signals to yield resultant signals having information relative to the motion of said pic torial subject, said analyzer circuit means including means for subtracting the signal recovered from one of said storage tube devices from the signal recovered from another of said storage tube devices, and means for operating on the difference signal produced by said subtraction with a pair of quadrature phase detectors so as to yield signals containing information relative to the vectorial components of motion of said pictorial subject, said signals containing the vectorial information being further operated on by means including a plurality of multiplier circuits so as to yield signals approximating the vector com-- ponents of motion of said pictorial subject, and means for feeding back said resultant signal to one of said storage tube devices.

10. A system for estimating the motion in a televised pictorial scene comprising first, second and third storage surfaces, means for storing video signals, representative of the pictorial scene, in a rectilinear scanning pattern on the first and second storage surfaces, means for storfirst storage surface in the rectilinear scanning pattern for deriving a first signal, means for scanning the second and third storage surfaces in a scanning pattern which results from the superposition of a circular scanning pattern on the rectilinear scanning pattern for deriving second and third signals, respectively, and computing means supplied with the first, second and third signals for deriving output signals which represent a measure of the motion in the pictorial scene since the earlier predetermined time.

ROBERT E. GRAHAM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,769,920 Gray July 8, 1930 2,202,605 Schroter May 28, 1940 2,293,899 Hanson Aug. 25, 1942 2,306,435 Graham Dec. 29, 1942 2,321,611 Moynihan June 15, 1943 2,381,902 Goldsmith Aug. 14, 1945 2,403,975 Graham July 16, 1946 FOREIGN PATENTS Number Country Date 324,399 Great Britain Jan. 27, 1930 909,949 France Jan. 14, 1946 

